1. Field of the Invention
The invention relates to a high water liquid enzyme prewash composition essentially free of hydrotropes, solvents and dispersants other than nonionic surfactants, in which enzymes are stably suspended in a structured liquid matrix and are further protected against deactivation by free water.
2. Brief Statement of the Related Art
Many liquid detergent and prewash (or prespotter) compositions have been formulated to meet the need for pretreatment of particularly problematic fabric stains, whether oily, particulate or enzyme-sensitive. Each of these products suffers from various drawbacks. Gelled or semi-solid prewash sticks require direct, mechanical application to the fabric and may not be desirable for all purposes. Liquid products are convenient to use but, typically, are limited in purpose since many are formulated primarily to attack oily stains. For example, Barrett, Jr., U.S. Pat. No. 3,741,902, discloses a laundry prespotter in which large amounts of organic solvent and a nonionic surfactant are combined to produce a nonaqueous composition. However, high amounts of organic solvents in products are disfavored because of current regulatory schemes. Bogardus, U.S. Pat. No. 3,761,420, discloses a stabilized enzyme stain remover in which enzymes are protected from deactivation in aqueous matrix by large amounts of glycerol, a solvent. To similar effect are Barrett, Jr., U.S. Pat. No. 3,746,649 (variety of solvents), Weber, U.S. Pat. No. 4,169,817 (propylene glycol), Landwerlen et al., U.S. Pat. No. 3,860,536 (propylene glycol), Fry, U.S. Pat. No. 4,767,562 (propylene glycol) and Kandathil, U.S. Pat. No. 4,711,739 (insoluble polyether polyol and hydrocarbon solvent).
However, none of the foregoing references teaches, discloses or suggests a high water liquid enzyme prewash composition essentially free of organic solvents, hydrotropes and dispersants other than nonionic surfactants in which the enzyme is stably suspended in a structured liquid matrix caused by interaction of the nonionic surfactants in the highly aqueous medium and in which the enzyme is protected against deactivation by water by said structured liquid matrix.